PPFS-AG-SG-7



	<H1><CENTER>BLACK "SOOTY" HEAD MOLD OF WHEAT</CENTER></H1><BR>




	<H3>Donald Hershman	</H3>					(Revised 7-94)<BR>






	Just prior to and during wheat harvest each year, the Plant Disease Diagnostic Laboratories at Princeton and Lexington receive many samples with questions about severe head molding. This condition is known as black or sooty head mold. Sooty molds are caused by a large number of weakly parasitic and saprophytic fungi, especially species of Cladosporium and Alternaria. Affected heads exhibit extensive dark, olive-green, and black discoloration; this discoloration gives the heads a very weathered appearance.<BR>




	Sooty mold fungi colonize wheat heads when wet, humid weather occurs during the latter stages of grain development and crop maturation. Molding is frequently most severe when harvest is delayed. In addition, heads that are shaded, weakened, undersized, or prematurely ripe are frequently affected by sooty molds. Head molding is also prevalent when plants are deficient in nutrients, lodged, or damaged by insects or other diseases. Severe sooty mold, thus, is a red flag that other production problems may also be affecting the crop. However, this is not always the case as many high yielding crops ca be affected by sooty mold in any given year.<BR>




	Sooty molds colonize and develop on scenescing and damaged tissues when weather conditions are favorable for fungal growth. All of the sooty mold samples received by the laboratory are usually superficial in nature. That is, the tissue surrounding the grain is affected, but the grain itself is not. This condition, although rough in appearance, does not significantly affect crop yield or test weight. A related disease, known as black point, results in damaged (discolored) grain which does affect quality and marketability. Black point, however, is rarely a significant problem in Kentucky.